Method of making printing rolls



May 12,1953 w. H KING 2,638,050

METHOD 0F MAKING PRINTING ROLLS Fiiediuay 28. 1952 IN V EN TOR.

Patented May 12, 1953 METHOD MAKING PRINTING ROLES William; Hz: Kin-g, West Springfield; Mass.,,v as Signor; to: Multicolor Gravure- Gorp- Elorenee,w

Mass:,

at corporation of Massachusetts Anglicatibn May'28, 1952;SeriaI-Nb. 2902590 4:2(3laimsza (Cl. Mlle-40112) invention relates t'o' new useful" 1m:- movements inthe general? art of, gravure printingv and has particularreferencetoa prooess of producing printing elements by which a" type? of printing; to be; referred to and identified herein as a: gradient printing; maybe accomplishedi My" invention: is directed morepartioularl'y to the provision of a methocrorrprocess of producing printingielement's, such? as are used" in gravure or liltaglib printing" as well as:- to the printing 81 35 mentitseli".

am printing surfaces used in the gravure method; thesubject matter to: be printed is represented by ink retaining cells or recesses of depths Whlbh. vary in accordance with the depth of? the-' color tones t'o be; reproducedi That? is, the deep tones of a, print will" be produce-Cl by]; those cells which: carry" the. most i'nk while-w the li'ghter tones: will? be" produce-d by the more shallow cells whiehvcarry lessink; tl 'ie harmom'Zing:iirteizxiiedi ate tones' being prodizced byr intervening cells of proportionate depths;

It: is oftentimesdesirableta print a" subject matter" in such a: manner that certain of the: printed areas are; darker-in their coior' or tone than certain other of the printed areas. In other words-; for various reasons: it. may: bev desired? to cover-the material being; printed v upon; one portion of? thearea-v thereof; with: kind? off printing: \vhieha decreases in" intensity uniformly between twee points; on areas. or 'whichy decreases; in". interwsity: uniformly between. twe points: or: areas, or; which decreases; intensity uniformlm between one point: or; area to: another: point: or: area where theneiiseno;pnintingwhateverz. Iidefihethistype of. printing; forrlacla 0i 2:, hetteri' name; as: gradient printing; Bymeans: thereof; these; differently printediaiteasoare blended smoothly amdiuniformly; into each other in a progressive; mannen That is; .the rise or:asoent'fromithetlightly-printedareas tow-theheavily'printerilareaaisaccomplished:grade ually andiuniaiomnly by degreesimsueh: a: manner thaflthe diiteremzes between: the areas themselves andfth'e various:gradations"therebetiveenareisub'l- Ste-maimimperceptible due. to\ the; uniform; and progressive employment; at more; and? moreinlzzin: the uniformly and progressively darker? areas;

It; therefore an: object: of" my invention to PEOV-iGBVEiIIDMEEi construetiomoi atprintingi element hye'whi'ch: afiim: ori'inlr; of. uniformly. deereasingson increasing: intensity'maybe applied; to the. mate rial. warmest, uponi whereby a gradient or graduated, efiieet' is obtained.

It. another oba'ject ofi my imzent'ihnt to; nrovide am improved intagiio printing element by: which:

2; the subject matter may be printed withgreenbelt fidelity-asto all'tonal: gradations: than has heretofore been possible.

In other Words; Iiprovi'de hereini a: noveliand improved method:v of makinga", printing? element? for applying an ink or coating-0r markingrmate rial in predetermined quantities torpredetermined areastof BJFSHEEtTOIJWI-BUL In orderto-attaintthis aiorementioned' effeotoi gradient printing and in. orde tos accomplish: the above ObjBotS-JOE my: invention; 1 have conceived an; arrangement: whereby the surface of: at prime ing element is provided with ink carryin t 032118 whiehi are of varying: depths; Bythisiarmngemerit, I; amabl'e toproduce gradientzprintingzmoreeasily, and; readily than has heretbfizne: been possible. i

As is well: known; in? thee art; printing: plates; 01' rolls used in gravulie-printing};rooesses.aneformed with; printingsurfaces comprisin ax multiplicity! of ink receiving; cells: 01%18668583; which ate; semiratedfrom; each. other by: rela iv lyynarmvwcrisscross; areas lenown asilancls ovenwhich the cleaner or; doctor? blade; rides:v after: the, plate. or; 1501i has been; inked: in: omen to remove; the: surglus; ink before; printing;.. 'lihese cells are. normally of a uniform sizegbutoi varying depths. 'Ihe: deeoest cells: naturally receiiiethe;greatestamount oi; ink. and: print the darkest tones in-the; picture. Cells intermediate depth: pnintshaded: on lighter tones in the picture while the highlights; are printedby very shallow cells: holding relatively smalls quantities; of ink,

In ordinary eravure. WQfiki, the one value dap' nds up n the depth the; cells; theweils: being normally etched; into the: plate; or roll: by M15901? the wellknownpreeessess Gonsiderabledifiicultghas: been experienced 11183133513 attaining; the proper and; desired: gradation the; dentin the ink: bearing: cell's 0191780885831, By means? of invention ire-any oi the problems:- associatedi with this-workhavebeen solved.

Another important object: of: l'lhEzDDGEQRtZiIH/Tfillr tiom. therefore; is;to1 provide: an impmvedigravure printing surface for intaglio printing; rolls and thelilse which makespossibleafull range of tonal valueswith ink recesses:

To a omplishthis: object, provide; a priming. rollor the like: wherein the: tonat gradatinnm are accomplished: by: varying the dimensions: 02? the ink carrying recesses and so control. theinsizei shape, and: arrangements that a full range at tonal values may be. achieved; without: flooding" antl' withoutzani excessive use of ink All of the above cited objects, I accomplishing means of such structure and relative arrangements of parts thereof, as will fully appear by a perusal of the description below and by various specific features which will be hereinafter set forth.

To the above cited and other ends and with the foregoing and various other novel features and advantages and other objects of my invention as will become more readily apparent as the description proceeds, my invention consists in certain novel features of construction and in the combination and arrangement of parts as will be hereinafter more particularly pointed out in the claims hereunto annexed and more fully described and referred to in connection with the accompanying drawings wherein:

Fig. 1 is a side elevational view of a printing cylinder of my invention having a portion thereof engraved, knurled or otherwise scored as a preliminary step in the method of making my printing element;

Fig. 2 is an end elevational view of the cylinder shown in Fig. 1;

Fig. 3 is a greatly enlarged fragmentary elevational sectional view taken substantially along the line 33 of Fig, '2;

Fig. 4 is a view similar to Fig. 3 showing a fur ther step in the method of making the cylinder and in which the depths of certain of the cells or recesses have been decreased:

Fig. 5 is a view similar to Fig. 3 showing a still further step in the method of making the cylinder; and

Fig. 6 is a side elevational view of a gravure cylinder similar to the one shown in Fig. 1 showing the finished roll made ready for operational use by the method of my invention. It is to be understood that wherever in this description the term printing roll is used, the same is intended to include either a cylindrical printing roll or a fiat printing plate.

Referring now to the drawing more in detail, in which similar characters of reference indicate corresponding parts in the several figures, and

referring more particularly to the preferred form of my invention selected for illustrative purposes, I have shown an intaglio cylinder generally designated by C comprising a cylindrical member of the desired diameter and length and mounted upon a suitable shaft M for use in a rotogravure printing machine.

Initially, the cylinder C will have a plain or smooth peripheral surface. A central portion or area upon the cylinder, depending entirely upon the printing requirements involved, is'then engrayed, knurled or otherwise scored as at 20 in any conventional manner so as to provide a systematic pattern consisting of a multiplicity of preformed recesses or cells 22. These recesses may take the form of inverted semi-spherical cup-like pockets, all as may be desired.

The depressions formed by the knurling are of any desired depth depending upon the maximum tone value desired in the printing operation.

In the illustration provided herein, it is desired to apply a substantially centrally disposed strip of ink or coating material to the material such as a web being Worked upon. Accordingly, only the zone or portion designated by the numeral 20 is knurled. Annular zones or areas 24 at opposite ends of the cylinder are initially left in their original state. That is, in the case of the cylinder shown in Fig. 1, the knurling will be observed to be centrally disposed upon the mem- 7 her C.

It will, of course, be understood that any portion of the cylinder or, in fact, the entire area thereof could be so treated in order to accomplish the objects of the invention.

Conceivably, the depth of the depressions 22 made as a result of the engraving or other operation might be between 0.0018 and 0.0025 in order to produce a certain result although such dimensions are not to be considered as restrictive or limitative in any way. Expressed in another way, there might be provided approximately cells or recesses per linear inch of engraving. It is to be understood that the cells are obtained by the intersecting grid lines whereby ink recesses or cells which are of the desired configuration are separated bythe relatively narrow lands 2B.

The pattern obtained by the engraving or knurling is similar to the pattern normally obtainedwith an etched screen pattern in known prior art devices and as in the case of same, depending upon the maximum density of the printing or coating desired, may be of any desired number of lines to the inch.

That is to say, the recesses may be in the shape of inverted cones with their apexes directed downwardly into the cylinder C and having their bases open for free delivery of the ink or coating material without restriction.

The recesses or pocket-like surface indentations are minute and equal and uniform and as aforesaid have an inverted pyramidal or inverted frusto-conical contour distributed over the entire area or at least a portion of the area of the cylinder.

By reference to Fig. 3, it will be observed that at a result of this knurling, I have provided upon the surface of the cylinder a plurality of lands 26 with cells or recesses 22 therebetween.

Certain of the portion of the knurled area 20 is thereafter stoned or lapped in a manner best shown by Fig. 4 whereby certain of the ink con-v taining cells are reduced in size and consequently in depth. That is, the outermost portions of the knurled area 20 are stoned or otherwise polished and smoothed so as to remove certain portions of the lands.

The stoning operation is so performed that each cell in an outer annular row of cells is uni-1 formly smaller than each cell in an inner adjacent row. As the stoning is carried out, the cells of each annular row of cellsare made progressively smaller in a direction. from the midsection of the roll to the outermost edges of the portion 20. Thereby a slowly taperingeffect is obtained from the innermost or central annular row outwardly toward the outermost annular row on each side of the knurled area 20 so as to accomplish the general effect shown in greatly exaggerated form in Fig. l.

Following the stoning operation, the outer plain surfaces 24 of the cylinder are polished or otherwise machined so as to reduce the same to a diameter equal to the diameter of the cylinder at the outermost edges of the annular portion 20 whereby an overall surface is produced witha smooth joinder between the portion 20 and the annular portions 24 and 24. I

For the purpose of explaining my invention, I

shall illustrate the invention as applied P ularly to the coating of a plastic sheeting or webbing although it will be understood that'my invention is by no means limited thereto and is applicable to printing or coating generally;

In the coating of this webbing, I employ an ink constituted by an aqueous mixture 1 of'a, print ing ink having a predetermined viscosity and used so as to achieve the result of the sheeting or webbing receiving on its surface the ink deposits from the recesses at spaced positions whereby the deposits of ink may gravitate or merge into a film of the desired tone values.

When an inking or coating operation is being performed by means of a gravure cylinder having the engraved or knurled surface, the amount of material is governed or predetermined by the size and depth of the cells. Normally such a gravure roll is entirely inflexible in the matter of varying the amount of material which may be applied therewith.

By means of my invention, if it is desired to reduce the quantity or amount of ink or coating material applied with a given gravure cylinder, this may be accomplished by partially stoning the cells at the desired area, which procedure has the eifect of reducing the depth of the cells so that the quantity of the ink or coating material picked up thereby will be reduced.

The effect is to produce in the lighter portions of the printed surface, the printed squares or circles or dots, as the case may be, are slightly separated from each other. In the darker portions of the printed surface, the squares or circles or dots are larger and overlap each other at their corners so that they lose their separate identity.

It will be understood that the transfer of ink need not necessarily be directly from a gravure roll or plate to the material being printed upon insofar as the scope of this invention is concerned. That is to say, the transfer may be from the gravure roll or plate to a rubber roll or plate which in turn produces the impression upon the material being printed upon. By this method, the transfer of ink is indirect instead of direct.

Further, it will be understood that although in the illustration provided herein an annular band or area around the periphery of the roll has been disclosed as having been so worked by the method of my invention, it will be understood that the area could be of other forms and configurations distinguishable from a band. Firstly, the hand or other design could be provided at one end of the roll, or at both ends thereof or at points intermediate thereof but not centrally thereof. Likewise the area of the roll so worked could be an area having a longitudinal axis parallel to the longitudinal axis of the roll instead of transverse thereto as in the form disclosed herein. Further, the area of the roll so worked could be disposed over the surface thereof in any other manner in order to produce any possibl desired gradient effect.

The invention may be embodied in other specific forms without departing from the essential characteristics thereof. Hence, the present embodiments are therefore to be considered in all respects merely as being illustrative and not as being restrictive, the scope of the invention being indicated by the appended claims rather than i by the foregoing description, and all modifications and variations as fall within the meanin and purview and range of equivalency of the appended claims are therefore intended to be embraced therein.

What it is desired to claim and secure by Letters Patent of the United States is:

1. The method of making a printing roll for printing a zone of ink which progressively increases in density between opposite sides thereof consisting in, forming a multiplicity of uniform and disconnected ink-carrying depressions of uniform predetermined area and depth in the normal smooth surface of the roll body throughout an annular zone having an outer side spaced inwardly from an end of the roll body and an opposite inner side spaced longitudinally therefrom, progressively removing the surface of the roll body within the zone to reduce the area and depth of the depressions progressively from one side of the zone to the other side thereof, and removing the surface of the roll body between the end of the roll and the outer end of the zone to a plane substantially in the plane of the bottoms of the depressions.

2. A method of making a printing roll for printing a zone of ink varying in density between opposite ends thereof, forming a multiplicity of uniform and disconnected ink carrying depressions of uniform predetermined area and depth in the normal smooth surface of a roll throughout a zone having outer sides and an intermediate point therebetween spaced inwardly of opposite ends of the roll, progressively removing the surface of the roll within the zone from the intermediate point to the opposite ends thereof to reduce the size and depth of the depressions progressively from the intermediate point to the opposite ends of the zone and in removing the surface of the roll without the zone to a plane substantially in the plane of the bottoms of the depression at the outer ends of the zone.

3. The method of making a printing roll for printing an area of graduated and decreasing density consisting in, providing on the roll surface a multiplicity of disconnected cells of substantially uniform ink carrying capacity in a certain annular printing zone on said roll, said printing zone being adjacent a smooth nonprinting zone of said roll, progressively removing at least a portion of the surface of said roll within said printing zone thereby gradually and progressively reducing the depth of said cells from the one side of said printing zone adjacent the non-printing zone of said roll to the opposite side of said printing zone spaced away from the non-printing zone of said roll.

4. The method of making a printing roll for printing an area of graduated and decreasing density consisting in, providing on the roll surface a multiplicity of disconnected cells of substantially uniform ink carrying capacity arranged in a certain unbroken annular printing zone extending around the roll and having a transverse width extending longitudinally of the roll and opposite side edges extending around the roll, and removing progressively across the Width of the printing zone and longitudinally of the roll at least a portion of the surface of the roll within the zone thereby progressively reducing the depth of the cells across the zone from one side to the other thereof and longitudinally of the roll.

WILLIAM H. KING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 227,782 Hoen May 18, 1880 1,490,414 Brogan Apr. 15, 1924 2,199,228 Obenshain Apr. 30, 1940 2,338,558 Wickwire Jan. 4, 1944 

